One-step synthesis and gas sensing properties of hierarchical Fe doped Co3O4 nanostructures

Co3O4 with hierarchical nanostructure was prepared by a low-cost and environmentally friendly one-step solvothermal method. In the process of material synthesis, ethanolamine (EA) was used to assemble nanosheets in a way to have flower-like hierarchical morphology. The crystallinity and valence state of the prepared materials were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was also used to demonstrate the extraordinary 3D nanostructures characteristic of the materials. The gas sensing properties of the as-prepared pure Co3O4 and Fe-doped Co3O4 were tested toward various gases. The results showed that the sensor based on 6.0 at% Fe-doped Co3O4 exhibited the optimum performance, with the highest response of 18.2-100 ppm xylene, a fast response time (40 s) and recovery time (35 s) at a low optimum operating temperature of 175 °C. It's worthy to mention that for a Co3O4-based material, the optimum operating temperature of the nanomaterials prepared in our study is much lower than those reported in previous literature.